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The development of object permanence was investigated in black-billed magpies (Pica pica), a food-storing passerine bird. The authors tested the hypothesis that food-storing development should be correlated with object-permanence development and that specific stages of object permanence should be achieved before magpies become independent. As predicted, Piagetian Stages 4 and 5 were reached before independence was achieved, and the ability to represent a fully hidden object (Piagetian Stage 4) emerged by the age when magpies begin to retrieve food. Contrary to psittacine birds and humans, but as in dogs and cats, no “A-not-B error” occurred. Although magpies also mastered 5 of 6 invisible displacement tasks, evidence of Piagetian Stage 6 competence was ambiguous.

Object permanence, the ability to understand the continuing existence of objects temporarily not visible, is a fundamental cognitive skill that provides a basis for many elaborate cognitive processes. In humans and nonhuman higher vertebrates, including birds, object permanence develops in a staggered manner. Studies on ring doves (Dumas & Wilkie, 1995); pigeons and mynahs (Plowright, Reid, & Kilian, 1998); kakarikis (Funk, 1996); Illiger macaws, parakeets, and cockatiels (Pepperberg & Funk, 1990); and grey parrots (Pepperberg & Funk, 1990; Pepperberg & Kozak, 1986; Pepperberg, Willner, & Gravitz, 1997) have demonstrated interesting parallels but also marked differences between avian species in terms of the performance level achieved and the...